[Cathepsin L from human brain tumor. Purification and contents]

Cysteine cathepsin L was isolated and purified 1242-fold from human brain. Cathepsin L pH-optimum, Vmax, K(m), lysosomal origin and thiol nature were determined. The distribution of cathepsin L activity in human brain tumours of different histological structure, histogenesis and degree of malignization was studied. The activity of cathepsin L in most the tumours was found to be higher compared to the normal brain tissue.